Field of the Invention
The invention relates to a method for controlling time based signals.
Especially in the technical field of Enterprise-Control System Integration (see e.g. Standard ISA-dS95.00.01-2000, Draft 15, January 2000), it is a major goal to monitor and control time related signals in process management.
Such a control domain shall include the functionality of monitoring production and either automatically correct or provide decision support to operators for correcting and improving in-process functions. These functions may be intra-operational and focus specifically on machines or equipment being monitored and controlled, as well as inter-operational, tracking the process from one operation to the next. It may include alarm management to make sure factory person(s) are aware of process changes that are outside acceptable tolerances.
For this purpose, different kinds of time signals have to be monitored via a monitoring device such as signals representing so called “closed states”. The “closed state” time signals are monitorable over a first time range of a first process with a first defined/known start time and a defined/known end time, in which the present time is signalized at a monitoring device by a time bar (also called Gantt bar/chart), and commonly for example in form of a spatially and timely extensible and uniformly highlighted portion of the first time range comprised between the first start time and at least the present time. At the end time of a process, the highlighted portion covers the entire predefined time bar.
A second type of signals is the so called “open states”. The “open state” signals are defined for states that have an associated second start time but not yet an end time. They are particularly important for a downtime analysis because they are still valid at the moment of the analysis.
A problem of present monitoring solutions is the fact that “open state” signals are monitored and signalized in a same manner as “closed state” signals, thus making it difficult to differentiate between the two types of signal states.
One goal to be achieved is to provide a monitoring device which makes it possible to differentiate between an “open state” signal and a “closed state” signal.